|
On
October 25th an extremely interesting special
exhibition was opened at the IMA (Institute du Monde
Arabe – the Institute of the Arab World) in Paris. Drawn
by the interesting subject and the incredibly beautiful
logo of the exhibit (an ancient “astrolabe” or starguide)
I went to see it on the day after the opening. I had
expected long lines of people waiting to enter,
especially since there are school vacations in Europe
now, but it was surprisingly and pleasantly quiet. Word
needs to get around.
It might have
been better to talk about the Golden ERA of Arab
science, because the period in which Arab scholars
contributed significantly to the progress of almost all
sciences covered many centuries, approximately from the
8th till the 15th century. The
area that was involved was huge – from Andalusia in
Spain to the borders of China the common language was
Arabic and from Samarkand to Saragosa the religion of
the majority of the people was Islam. Unlimited
curiosity, a desire for knowledge, confrontations with
other cultures through travels and pilgrimages, and a
sense of progress paint a picture of a dynamic society.
From the 9th C. onwards Arabic was the
language of philosophy, medicine and mathematics. The
Arabs translated almost anything they could lay their
hands on, except literary works such as the Iliad and
the Odyssey. Already in 832 the Abbassidic caliph al-Ma’mun
founded the first scientific institute of the empire –
the ‘beyt al-Hikmah’, where there was a large
library that scientists, philosophers and translators
could use. The monarch provided support for expeditions
to Byzantium to research Greek manuscripts and founded
an observatory as well as several hospitals in Baghdad.
The scientists of
these times were not only Islamic scientists – they
included Christians, Jews, Zoroastrians and even
atheists among their number.
Some names that I
encountered in the exhibit were well known, like that of
Ibn Sina (a.k.a. Avicenna), the father of modern
medicine, and that of the founder of algebra,
mathematician al-Khwarizmi, who gave his name to
“algorithm”. On the whole, however, the exhibit
introduced many lesser-known names and inventions by
means of hundreds of ancient manuscripts, displays of
ancient tools and equipment, concise information posters
and many films as well as some reconstructed engineering
and entertainment devices.
I can only give a
brief synopsis, hoping to raise enough interest that
readers may go to see for themselves the scientific
heritage that was left by the ancient Arabs.
Science was
introduced in the Arab world through translations of the
works of Greek, Roman, Persian and Indian scientists
that went before. These works, for instance those of
Ptolemy, were examined, analyzed and improved upon. Arab
scientists discussed the problems of the earth’s
rotation and made up astronomic tables for various uses
that helped with the orientation of mosques and the
fixing of the prayer times and of the appearance of the
moon’s crescent. The Arabs became famous very quickly
for their astronomy and their navigation. They made
geographical charts and 3-dimensional models of the
heavens. A few of these intricate and beautiful
celestial globes that give mirror images of the stars
and constellations, dating from the 13th tom
18th century, were on view.
Astrology had
long been used in other cultures as an instrument of
prediction and as a political instrument (to appoint
leaders) and it became important in the Arab world also.
In medicine the
Arabs followed the descriptions of the human body and of
illnesses mainly recorded by Gallenus and handed down
through the Greeks, but Ibn Sina gave structure to this
medical knowledge and demonstrated cause and effect in
illness. He also set up hospitals (a famous one in
Damascus) that were both for the care of the sick and
for the education of young doctors. Ibn Sina, who was of
Persian origin, wrote over 200 books, mainly in Arabic.
The two main works, one about medicine and one about
logic, physics and metaphysics were translated into
Latin and had great influence on medieval scholars.
An important
discovery was that of the decimal point – necessitating
the use of the number 0.
The history of
“zero” is an interesting one. The Egyptians ignored it,
the Greeks paid no attention to it, and the Romans
denied it existed. It first appeared in Babylon, several
centuries B.C., as two small ticks representing an empty
space. It was only in India, in the 5th C.,
that it was given a special meaning. In 628 the
mathematician Brahmagupta defined it as the subtraction
of a number by itself and called it “sunya”. Its
characteristic was (and is) that when it is multiplied
or divided by no matter which number it always results
in 0. The Arabs encountered this number on their travels
to China and called it “sifr”. Through the works of al-Khwarismi
it reached all over the world. The Christian church
first condemned it as an instrument of the devil, but it
became a favoured tool of merchants because it made
their calculations easier. It allowed the introduction
of negative numbers and created the possibility for
Newton and Leibniz to invent differential calculus – and
thereby gave birth to modern computer sciences.
Chemistry did not
become a real science until the end of the 18th
C. but scientists were always trying to find means to
turn ordinary substances into gold – a science called
alchemy. Two Arab scientists were famous alchemists:
Jabir ibn Hayyan (latinised as Geber) and Muhammad ibn
Zakariyya al-Razi (known as Rhazes), the father of
chemistry. The latter described in detail tools and
chemical processes and classified the elements in a
systemic manner. He was a clinical medical doctor, as
well as a surgeon, a gynecologist and an optician. He
died in 923 and left two famous works: al-Hawi
and al-Mansuri.
In the exhibit
there is a beautifully illustrated explanation on view
of how to distill rose water, written in 1237 by al
Dimashqi.
In the field of
optics the knowledge that was already present was
studied, verified and improved by various scientists
from the 9th till the 14th
century. The greatest of these was Ibn al Haytham a.k.a.
Alhazen, who died in 1040 and whose books on optics (Kitab
al-manadhir) remained a work of reference until the
end of the 17th century and was the main
source of knowledge for people like Kepler and
Descartes.
Three very rich
brothers Ahmad, Muhammed and Hassan Banu Musa in the 9th
C. were fascinated by mechanics. They had the works of
Archimedes “On spheres and cylinders” and “On measuring
a circle” translated into Arabic. Later they wrote their
own treatise “On measuring surfaces and spheres”, which
was translated into Latin and served as a teaching text
till the 14th C. Their book “On ingenious
processes” describes hydraulic systems, watches, heavy
lifting cranes and automatic lights and locks. A model
of a pumping system that operated with a series of
pistons was on show. Unfortunately none of the robots
that they designed for entertainment survived till this
day, but a pretty replica of a household scene was
present in which water was used to propel small
figurines around the house, pop up camels and goats next
to the well and even make a set of cobras dance!
In architecture
Arab designs have long been famous. At first
architecture followed the earlier Greek, Roman and
Persian designs, but later the sculptures, especially
those of people, disappeared and decorative motives
based on Arabic calligraphy became more prominent.
Geometry and arithmetic were directly used in the
various stages of design and realization, specifically
in the creation of the enormous vaulted ceilings of
mosques and palaces. Mozaics, intricate pavings and
muqarnas are typically found in Arabic architecture.
Even music is a
mathematic discipline – this was said by the Greek
Euclides. The Arabic scientists al-Farabi and Ibn-Sina
considered it to be a science and not a means of
amusement. It deals with the nature of those objects
that produce sound, with melodies and rhythmic cycles.
Mathematical theories underlie the melodies. As Ibn-Sina
wrote: “Music is a mathematical science in which one
studies the relationship of sounds and establishes them
as a function of their consonance and of their
dissonance, as well as a study of the duration of time”.
In the exhibit a video film describes the differences
between Western and Arabic music that can be explained
by mathematical equations. Apart from an interesting
science, the early Arabs considered music to be a
therapy for sick people!
The ‘ud
was first made in the 11th C. by ibn Zayle,
and also the qânûn dates way back. However, the
many musical instruments that the exhibit showed, mainly
dated from 19th C Egypt.
It seems strange
that with such a dynamic past the Arab world found
itself in such a decline scientifically after the 15th
century. In an interview Ahmed Djebbar, commissioner of
the exhibition and himself a mathematician and
historian, explained some of the relevant events.
From the 11th
C. onwards the Islamic empire was under attack, first by
the Crusades, then by the Mongols. The loss of territory
had an enormous psychological effect. People started to
behave differently, defensive rather than offensive.
There was an economic decline also, and there were
incessant political battles. During the Golden age of
Arab science, the theologians could not counteract a
powerful phenomenon. But towards the end of the 13th
century their influence became noticeable. And even
then, the decline was not equally severe in all parts of
the former empire. In Spain the Arab influence had gone
by the 15th century, and in the Maghreb it
was just beginning. However, in Samarkand research
continued in astronomy and mathematics. There is no
verse in the Quran and no Hadith that objects to the
practice of science. In fact the Prophet has said: “one
must not bless the day in which one has not acquired
more knowledge”. The theologians explained this as
referring only to the knowledge or science of religion.
They were especially wary of astronomy and astrology.
However, the opposition of Islam to science never took
the extreme form of that of Christianity. The latter’s
theologians had scientists burned at the stake for
making claims that were considered blasphemy. Such
things never happened in the Arab world with scientists
and till today the Arabic word for science “ ‘ilm”
commands respect. | 
